OBJECTIVE: To assess the association between spicy food consumption and chronic uninvestigated dyspepsia (CUD) in a large sample of Iranian adults. METHODS: In this cross-sectional study we assessed the consumption of spicy foods in 4763 Iranian adults living in Isfahan Province using a dietary habit questionnaire. A modified validated version of the Rome III questionnaire was used to assess CUD-related symptoms. CUD was defined as having one or more of the following characteristics: distressing postprandial fullness, early satiation and/or epigastric pain or epigastric burning at least often during the past three months. Information on meal regularity, meal frequency, intra-meal intake of fluid as well as other potential confounders was also collected. RESULTS: CUD was prevalent in 15% of the participants. The frequent consumption of spicy foods (≥ 10 times/week) was associated with greater odds of having CUD [odds ratio (OR) 1.64, 95% confidence interval (CI) 1.09-2.49, P < 0.05). This relationship was significant even after adjusted for diet-related practices (OR 1.68, 95% CI 1.01-2.79, P < 0.05). There was a significantly positive association between spicy food consumption and postprandial fullness (OR 1.76, 95% CI 1.29-2.40, P < 0.05) and epigastric pain (OR 1.78, 95% CI 1.30-2.44, P < 0.05). However, no significant relationship was observed between the frequent consumption of spicy foods and early satiation. CONCLUSIONS: High consumption of spicy foods is associated with greater odds of CUD, frequent postprandial fullness and epigastric pain. Further studies, particularly of a prospective nature, are needed to confirm our findings.